On Thu, Jul 1, 2010 at 7:10 PM, Yves Lafon <ylafon@w3.org> wrote:
> On Wed, 30 Jun 2010, Philip JÃ¤genstedt wrote:
>
>> On Wed, 30 Jun 2010 16:22:15 +0200, Yves Lafon <ylafon@w3.org> wrote:
>>
>>> On Wed, 30 Jun 2010, Philip JÃ¤genstedt wrote:
>>>
>>>> You cannot write a robust MF parser based on this grammar, because
>>>> t=1&foo=bar is not a valid production, meaning that any future extension foo
>>>> of MF will cause that parser to fail completely. Either the grammar itself
>>>> must be relaxed, or the parsing must be defined normatively and handle some
>>>> things which are not valid productions of the grammar.
>>>
>>> What do you mean by "robust" ?
>>
>> I mean that it doesn't stop working completely for future additions to the
>> syntax, that it should degrade gracefully. If browsers shipped with a parser
>
> Graceful degrdation should not be mistaken with "betraying intent", while
> graceful degradation is wonderful in many cases, you always have to be
> careful.
> ex: http://www.example.com/football.movie?xywh=10,20,30,40&action=track may
> mean "highlight this part (a ball), and track it", a MF aware client will
> just crop the identified part. That's not graceful degradation, that is
> betraying intent (regardless of the fact that the extra action=track might
> be a bad design).
> In CSS, properties with unknown values are ignored, to allow both graceful
> degradation (it doesn't impact _other_ properties) and forbid betraying
> intent.
Note that this is a URI query, so not much relevant anyway, since it
is up to the server to decide what to do with it.
However, assuming you meant
http://www.example.com/football.movie#xywh=10,20,30,40&action=track ,
I would agree with the CSS approach. If I am a UA that doesn't know
what to do with action=track, then I will ignore that part of the
fragment's name-value pairs and only interpret the first part. If that
results in giving a cropped video and nothing else, then that is fine.
It is better than ignoring all the name-value pairs and downloading
the full movie!
Cheers,
Silvia.